Mil-Dot Ranging and Focal Plane

[Graham Smith]

I have a fairly decent SFP scope that is set to do ranging at 10x. That's a fairly reasonable power to use but at 500yds and 10x a target is fairly small, and with mil-dots also being fairly small and relatively close together, it's a bit difficult to estimate if size of the target is 1.5 mil or 1.75 mil and at that distance that much difference is a big deal.

I tried the same thing with a FFP scope set at 10x and it was a lot easier to determine the height of the target, and when I cranked it up to 15x, it was even easier.

So, either I am really missing something here in how to use a mil-dot or having a FFP mil-dot seems to be a much better choice.

[mlmiller1]

I've got a ffp scope & am learning about ranging. It seems if you have plenty of time, ranging with a sfp is doable but the ffp is faster. Guys that are good at it with sfp scopes do fine but it is hard to learn to do well & quickly.

So, I think ffp is better, at least for me.

MLM

[double_r76]

SFP or FFP should be the same at 10x as long as the SFP is calibrated to range accurately at 10x magnification.

I would say that 10x is the absolute minimum for me to use a mil-dot reticle. Once you use a mil-dot or MLR reticle at 20x or 25x, you will never want to use anything else. That said, the stadia also appear pretty thick at that magnification, which can take some getting used to for precision shooting.

-Randy

[Wap wap]

the mil-dot reticle has been around awhile and is still being put in some of the newer under $1k scopes, why I don't know. hash marks are much easier, some sfp reticules such as the zeiss z series range as well as the ffps. The higher the power the less error which usually runs about 3-5% of the distance. a 8x32 nf br can reduce that error margin by 50% even in sfp. between the ranging advantages offered between sfp and ffp , ffp works better if using a spotter or for windage holdoff at any mag, and thats about it.

[cardiackid]

Like others mentioned, it's definitely do-able with an SFP mildot scope but it's an acquired skill and will get better the more you do it. Depending on where you live, set up some small objects in the yard or practice ranging items at known distances out of a window (IE, the stop sign down the street, car tires, etc. - anything you can measure in inches with a tape measure that is fairly constant). Once you have a known item at a known distance (even if you just pace it off) it will allow you to fine tune your ranging techniques and get a good feel for exactly where you mil a target from the comfort of inside your house. Oval versus circular mildots tend to make this a little easier as well. That was one of my major concerns when I purchased my new scope though and opted to spend some extra cash for Leupold's FFP TMR reticle (hash marks)- it's like ranging without a handicap now.

[blackstone]

You can range at any power with a FFP.

With a variable power 2nd FP scope, you can only range at max. power, without doing some additional math.

Stress plus an additional math step increase the probability of error on your part.

More importantly, to me, with a FFP scope, if you miss with your 1st shot, corrections are fast and easy.

Let's say you see your first strike at .4 mil.s low and off .2 mil.s left wind.

Regardless of your power setting, with a FFP scope, you now hold the above-referenced correction and fire again because what you "see" in the scope is in true mil.s regardless of the power setting. No conversions are necessary.

Lastly, make sure your turrets are in tenths of a mil.

In the above example, if you wanted to dial your corrections, it is as easy as four clicks up and two clicks of windage and fire again.

Front focal plane mil. reticles with one tenth mil. turrets reduce the complexity of quick adjustments under stress.

[AlamoShooter]

its even easier if you have the Fever

[Wap wap]

the degree of accuracy of ranging is determined by the magnification power whether ffp or sfp, ranging on lower power with ffp offers little or no advantage. Using a lower power ffp for increased fov, doesn't solve the problem either. A more accurate reading can be had with a sfp 32x than a 10x ffp. Shots under 300 yds usually don't present a problem under normal conditions, and 308 shots usually only run somewhere around 3 mil or 10 moa at 500 yds. 2nd corrections are simply fraction math, (but then 5 out 3 people have problems with fractions). In any case if you want to learn "milling" as an artform learn them all, if your really serious get a laser range finder.

[AlamoShooter]

2nd corrections are simply fraction math, (but then 5 out 3 people have problems with fractions). .

OK I can agree with most of this but I think your statistics are off.

Its 1.005 out of 0.300 people have problems with fractions = thats an Alamo Factoid=

[Biloxi23]

Not all SFP scopes are calibrated for Mil Dot ranging at maximum power. I have a Burris XTR (Extreme Tactical), 3-12 X50, that is calibrated for ranging at 10X. The power adjustment ring is marked at the 10X setting.

[ccoker]

I am a big fan of FFP and hashmark type reticles like the Leupold TMR, USO GAP Mil, etc..

[Wap wap]

Not all SFP scopes are calibrated for Mil Dot ranging at maximum power. I have a Burris XTR (Extreme Tactical), 3-12 X50, that is calibrated for ranging at 10X. The power adjustment ring is marked at the 10X setting.

very true some of the best sfp scopes made do their distancing in the middle range. The 6x24 diavaris (except for the z's) and the Nightforce Br series.

[Graham Smith]

I've seen several scopes lately that have gone to 10x for ranging. Some have even changed from a higher power. I believe that the reasoning is that 10x gives you a better field of view and is powerful enough to use regularly at distance without being too powerful to use on closer targets - after all, 10x fixed is an extremely popular scope in it's own right. That means that you can leave it set for 10x most of the time and only go higher or lower when needed.

[Wap wap]

I don't think a conclusion can be drawn. It makes no sense in the "art" of ranging to range at a lower power, the most accurate readings or calculations will come from the highest magnification in either ffp or sfp. In scope design, as an example, tactical scopes are designed for fast target acquisition at the expense of depth of field, whereas in a target scope depth of field is better. This is achieved at the expense of problems in parallax, or clean images in both planes. In a sfp scope, ranging at 1/2 of the highest power is simply a matter of 2x the highest power readings-- the relationship is linear. Ffp doesn't matter. So stating that the scope,in the case of the sfp, ranges at one power, either in the middle or the highest has no meaning, except that the buyer doesn't have any idea how the whole system works. The diavari mil-dots range in the middle for tactical applications whereas their diavari Rapid Z ranges on highest magn. for accuracy in reading. Scopes with higher quality glass such as the NF and Diavaris, USO,etc.etc. sometimes have what appears to be focusing problems when trying to getting the parallax set, because the better glass gives a more accurate rendition of the image plane. This is why one sometimes hear that some "cheaper" scope was amazing that when adjusting the parallax focus the image snapped into focus.

Current thought in ffp design is to have the "measuring" ability in the reticle transparent, until moved to the highest magnification , then the hashs or dots snap into the sight picture not the other way around. The EBR2 Razor and SS 1x4 are good examples and this trend will continue as it lets the shooter choice between a faster tactical mode at lower power or more refined "bench" at higher powers.

[Smokin]

As many have said here, the biggest issue with SFP is going to be the limitation on your maximum zoom. That being said, you will most likely be utilzing your max zoom for effective ranging. When you are working with smaller targets or targets at longer distances, the ability to differentiate between .05 Mil will be the difference between making the shot, or missing the shot. Good quality glass, understanding your reticle (many of the nicer reticles have "built in" tools to help you range such as lines with known thicknesses in different areas, etc.) You will usually use the lower mag to find the target, and the higher mag to range and kill the target. As an example, a 16" target that shows at .5 Mils is about 890 yards (roughly your 900 yard dope). However if youre a little off and its really .45 Mils then the range is 987 yards (your 1K dope) or if it is .55 mils you should be using your 800 yard dope. The significance is a BIG miss. On even a hotrod round...say a 6.5mm 139 Lapua Scenar, pushing 2900fps. 800 yard dope is roughly a 5.5mil comeup, 890 yards is 6.5mils of elevation, and 1K is 8 yards of comeup. The variation on a 308 using a 175 SMK would be MUCH worse. This is a very real scenario that is often used in many of the tactcal long range matches. The clarity of your glass, your real world experience ranging, and field conditions will come into play, but low magnification ranging can be challenging. FFP/2FP isnt really the issue.

Edited May 25, 2011 by Smokin

[Graham Smith]

I have not been able to fully research this, but it has been suggested that the only reason to do ranging at 10x when your scope goes to 15x is to be able to use the standard charts.

However, by using a laser range finder and a few different sized "targets", you can dial your scope to maximum power and create your own table (i.e. a 24" target at 500yds is x mils). Once you have done several of these, you can create your own ranging table that will be specific to your scope and may be more accurate than the general mil-dot formulas at 10x.

This would seem to make sense, mathematically, but it will take some testing to see if it does or if it is just hot air.

Edited May 26, 2011 by Graham Smith

[Smokin]

Standard charts? As long as your reticle is accurate at a particular magnification, how would the calculation of a target size to range be impacted? I have been shooting precision long range for years, and Ive never heard of this. Granted, I may always have something new to learn, this would be the first time I heard of a magnifiction dependent mil dot master.

If you have a SFP scope and the max zoom is 15X, your reticle is more or less meaningless at ~10X unless you REALLY know you are EXACTLY at 10x in which case you now have a second math problem to solve. If your scope is FFP, then the reticle is always accurate regardless of zoom, but I dont see the advantage of dialing back the magnification for ranging purposes. I use an S&B 5-25PMII and can not recall ever using anything other than 25x to do my ranging for UKD targets. If I am engaging multiple targets at varying distances (known) or a mover (at a known distance), I will dial back the magnification. This way I find the target easier and then use the FFP reticle for hold over shooting.

Edited May 26, 2011 by Smokin

[Wap wap]

Nightforce suggests recalibration of the range estimation using their sfp scopes in the product manuel of every scope they sell- if you don't like the one thats there. Exbal ballistics program and nightforces allow you to recompute the ranging and reticle drop of any of their scopes. Recalibration of the "milling distance" is particularly useful if your using a sfp scope for shooting 22lr at 300 yds. as an example, and don't want to mess with a 20 or 30 moa rail. Another useful feature is if your using a standardized target like a golf ball or tennis ball and want to calibrate between to hash marks for speed and ease of reference. If you are reloading and want to mess with simulations by changing the velocity figures of the gun your using, both Swaroski and Zeiss web site be used to "readjust" the ballistic profiles of their scope drop reticules,

Using a laser rangefinder is very good way quick and dirty way to recalibrate the ranging of reticle, but if you have a laser rangefinder why do it in the first place.

Distance range finding using some type of radial measurement (milling) is an urban and suburban sport. There are few objects in nature that you will be "ranging" on that will be of known dimension. Try it in the desert sometime.

[Wap wap]

As suggested the biggest down to ranging at different powers with sfp is lack of positive clicks on the mag ring to announce when your at that power. However some scopes , the Br NFs and some others, range on 22 not the highest power. With any scope one should check the tracking against a precise measure as well as the distance between the hash marks used against a scale. A simple yardstick at exactly 100 yds works great. When that position of the hashmarks coincides with the measurements on the yardstick, make a small mark on the scope power selector ring (or a great big one if you prefer). Why would you want to to this? Shooting movers at 200 yds and you want to dial down for increased FOV is one reason. Or you could just be curious.

Milling, regardless of sfp/ffp, selection will show between 3 to 5% error of the distance your reading, depending on quality of the scope, magnification etc. But thats only part of the problem, even if you know the exact distance your shot still depends on other factors.

If you know the exact velocity, ballistic profile of the bullet, have access to realtime ballistic information for variable input, (pressure,temp,wind) you can either compound the miss (tolerance stack up) or make the error read in the distance result in a more precise hit. (Just shoot and let the wind blow it in). More often the width of the target at the various distances will determine your percentages of hits because of changes in wind.

[Wap wap]

A source of confusion is ranging with sfp vs. reticle holdover at various powers. They are not the same. When using holdover parallax is used in positive sense to set the holdover distance of the ballistic curve of the round your using. But this trick can also be used to range. Swaro uses it their TDS reticle and Leopold (somewhat) in their BAS system. It rests on knowing the projectile curve between 200 and 300 yds., setting the magnification such that the hash marks coincide with a known height of the target, then calculating the distance. Since decreases in magnification on a sfp scope will move the reticle center under the target, a re correction on the shooters part will lift the muzzle for the distance correction. If you interested sometime use a scope with a high end and wide range in the magnification experiment walking the bullet in using magnification adjustments rather than holdover. Its a great learning experience and the effect is amplified when using 22.lr and long ranges.

SFP reticles have the advantage over ffp reticle (in most cases) of being able to quarter or bi-sect the target rather than shooting center of mass. So at the lower powers on sfp for the increased field of view (movers) its a little easier (and faster) to shoot the right upper hand corner for windage and distance correction than dial in. This technique is used by some of the biggies on tactical shooting competition.

Another misconception is that sfp do not change poi with changes in power and using dial in. For this to occur the erector magnification would have to perform exactly the same every time, which is impossible. Usually this random error is slight and irrelevant in better made sfp scopes.

[spraynpray]

If you are planning to do any competitive shooting that requires mil-ranging, FFP is the only way to go. Once the buzzer goes off, I have seen folks trying to range targets only to realize later that all their measurements were wrong because they were on the wrong scope power.

Could this be avoided with more practice and mental conditioning? Sure. At the end of the day, however, it is one less thing to worry about.

I have a Bushnell spotting scope with a FFP mil-dot reticle. I use it in tactical competitions with a pistol-grip head tripod for ranging and it works great. Also, when spotting shots, it is easy to give accurate corrections in mils. The spotter is also nice for practicing ranging in an urban area, because you don't have to point a rifle around, you just look like a birdwatcher (or a creep, depending on the size of your mustache). I will go to a city park with an overlook and make a practice range card by ranging trash cans, fences, park benches, picnic tables, etc, then check my work on google earth.

[tazjet]

it would seem that some people are missing the point. Mil dot uses the dot itself at time to range targets. I personally own a nf nxs in 5-22 ans 8-32. I use the scope to range everything. It takes time but practice will pay off in this case.

[Alaskapopo]

its even easier if you have the Fever

I just picked up a first focal plane vortex. I have not got to shoot it yet. Its a 2-16 PST with Mrads. I need to figure that system out as I am used to MOA.

Pat

[Graham Smith]

I just picked up a first focal plane vortex. I have not got to shoot it yet. Its a 2-16 PST with Mrads. I need to figure that system out as I am used to MOA.

I've never seen any Vortex scope with that large a range. Do you mean 4-16x ?

As to the MRAD, I assume you mean that both the reticle and turret are in mils. If so, your regular formula for come-ups will have to be changed and a mil-dot calculator won't work. On the other hand, if you are 2 mils low, all you have to do is add two clicks - it makes adjustments a dawdle.

Edited November 22, 2011 by Graham Smith

[mlmiller1]

My Mil/Mil scope has 1/10 mil clicks so on mine, if you are 2 mils low, you need to make 20 clicks. That would be approx 7.2" at 100 yds. With the typical 1/4 MOA scope, that would be 29 clicks, right?

Mixing the two, mil & moa is kinda like speaking German & French at the same time, in my mind. Either method is good but mixing gives me a headache. hahaha.